"I don't know the brand - not moving in until next month."

After you move in, determine the brand and model. Once you have that, it may be possible to determine the likely cutout size from its specifications without removing the cooktop from the countertop. It may then be possible to find an induction cooktop that would fit in the existing cutout, eliminating the need to modify the countertop.

Before buying a replacement, you'll want to verify the cutout size and and check the cooktop circuit to make sure it can handle the induction cooktop's power requirements. But move in, check the existing cooktop, and report back first. Happy move!